In recent posts, we’ve talked much about supervisory control and data acquisition (SCADA) systems, which are used to control and measure the performance of equipment in many kinds of industrial operations. We have also considered some of the limitations of traditional SCADA systems, and how they differ from modern internet of things (IoT) installations. However, we have not looked at some practical considerations for companies looking to either upgrade or replace existing SCADA systems with 21st century technology. Is it worth the cost and effort to upgrade an existing (brownfield) operation? Or, in terms of your return on investment, should you instead make the wholesale change to a new (greenfield) solution?
The high cost of maintaining legacy systems
When doing a cost benefit analysis for a new system, you are going to be faced with the cost of the new system vs. the alternative of doing nothing, i.e., the status quo. While it can be tempting to see the status quo as the cheapest option, this is not always the case.
In When Legacy Becomes Loss: The True Costs of Legacy Systems, Tracey Ruff identifies nine true costs of holding on to legacy systems, including:
The last two points underline the not-so-hidden cost of doing nothing. In a 2019 study from the US Government Accountability Office, 80% of the $90 billion IT budget for 2019 was earmarked for operating and maintaining existing IT investments, including legacy systems. These old systems become more expensive over time as their effective functionality ages. For example, “the selected legacy system at the Department of Education runs on Common Business Oriented Language (COBOL)—a programming language that has a dwindling number of people available with the skills needed to support it.” COBOL, by the way, was standardized as a programming language in 1968. SCADA came on the scene in the mid-1970s.
Legacy systems don’t become expensive to maintain overnight; rather, their cost increases through a gradual accumulation of technical debt over a period of years and decades. Make sure you do a full cost analysis before settling for the status quo.
How to build an incremental change path
For an organization with an existing SCADA system, the decision either to keep the existing system or rip it out and replace it with an IoT solution can be difficult to make. Thankfully, the decision doesn’t have to be binary, as there are multiple paths to an upgraded system, including:
Let’s consider these options.
By adding internet-enabled sensors to equipment whose operation or output is not measured by your legacy SCADA system, you get the immediate benefit of accessing this new data stream in a cloud environment. While the sensors won’t be directly integrated into your existing analytics systems, this may not be as important as having access to information you previously lacked. For example, if you’re having difficulty controlling temperature at a workstation, you could simply install a wireless thermometer connected to a self-contained app to monitor the situation.
Adding sensors in this fashion has a huge advantage in the speed with which they can be deployed and the agility with which the solution can be changed. On the other hand, adding sensors with different monitoring applications can result in technology sprawl that takes away from your goals of standardization and consistency. But as a proof-of-concept or as an emergency stopgap, this option is very powerful and does not require changes to existing infrastructure.
Another way to upgrade to an IoT solution is to first create a parallel IoT system that shadows the existing SCADA system. As with the previous option of incremental sensors, the advantage here is that no changeover is required from the existing platform.
Generally speaking, an IoT system consists of internet-enabled sensors that communicate directly with a central IoT hub in the cloud. Sensor data is sent directly over the internet, often wirelessly, negating the need for complex network architecture and equipment on-site. In cases where data traffic becomes burdensome, adding a network gateway on-site can help filter some of the IoT data traffic; however, this will become more the exception than the rule in the future as bandwidth continues to grow exponentially (and reduce in cost per gigabyte).
One of the biggest advantages of a modern IoT system is the data-driven insight it offers using modern analytics and reporting tools. By adding a shadow IoT solution to your legacy SCADA system, you can significantly improve your reporting and analysis.
Another advantage of building a shadow IoT solution is the ability to easily upgrade it in the future, as described in the next two options.
There are many limitations to traditional, on-premises (on-site) SCADA installations:
However, one of the advantages of traditional SCADA systems is that they already have access to pre-installed sensor data streams. Instead of replacing existing hardware, one option is to simply tap into these data streams.
Adding a network gateway to your onsite infrastructure easily solves this problem. The gateway connects directly to the existing SCADA system (or PLC stack), packages the incoming data streams into secure internet packets, and sends the data to a cloud-based IoT hub.
Since the IoT hub also natively receives data from IoT sensors, adding new sensors to the system is as simple as adding new sensors to the plant.
Nuff said. Forward-looking companies are typically looking to upgrade their brownfield installations as if they were greenfield. Mid- to long-term, all companies will change over to internet-enabled IoT systems for reasons including their advanced analytics capabilities, scalability and ease of integration.
Because cloud-based IoT solutions can provide better scalability, better reporting, better analytics and, ultimately, better value than SCADA systems, the trend toward this technology is inevitable. Companies looking to either test the waters or dive in headfirst have many options to upgrade their operations. If you’re unsure which of the broad approaches outlined in this article makes the most sense for your organization, you can start by speaking with one of our systems optimization experts.
The opportunity cost of doing nothing increases every day, so don’t let your default option prevent your business from evolving toward a more automated, integrated and analytics-driven future.
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